"(calcite), and about 5% iron oxides (hematite, magnetite, goethite?). These minerals are typical weathering products of mafic igneous rocks. Studies with magnets aboard the landers indicated that the soil is between 3 and 7 percent magnetic materials by weight. The magnetic chemicals could be magnetite and maghemite. These could come from the weathering of basalt rock. Experiments carried out by the Mars ""Spirit"" rover (landed in 2004) indicated that magnetite could explain the magnetic nature of the dust and soil on Mars. Magnetite was found in the soil and that the most magnetic part of the soil was dark. Magnetite"
"Hematite Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (FeO), one of several iron oxides. It is the oldest known iron oxide mineral that has ever formed on earth, and is widespread in rocks and soils. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above . Hematite is colored black to steel or silver-gray, brown to reddish brown, or red. It is mined as the main ore of iron. Varieties include ""kidney ore"", ""martite"" (pseudomorphs after"
"magnetite), ""iron rose"" and ""specularite"" (specular hematite). While the forms of hematite vary, they all have a rust-red streak. Hematite is harder than pure iron, but much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral. Huge deposits of hematite are found in banded iron formations. Gray hematite is typically found in places that can have still standing water or mineral hot springs, such as those in Yellowstone National Park in North America. The mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can also occur"
"clay, especially Armenian bole, have been used in gilding. Hematite is also used in art such as in the creation of intaglio engraved gems. Hematine is a synthetic material sold as ""magnetic hematite"". Hematite Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (FeO), one of several iron oxides. It is the oldest known iron oxide mineral that has ever formed on earth, and is widespread in rocks and soils. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at"
"titanomagnetite and hemoilmenite or titanohematite. Compositions of the mineral pairs are used to calculate how oxidizing was the magma (i.e., the oxygen fugacity of the magma): a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization. Magnetite also is produced from peridotites and dunites by serpentinization. Lodestones were used as an early form of magnetic compass. Magnetite typically carries the dominant magnetic signature in rocks, and so it has been a critical tool in paleomagnetism, a science important in understanding plate tectonics and as historic data"
"an important example of which is maghemite. Another series, the ""titanohematites"", have hematite and ilmenite as their end members, and so are also called ""hemoilmenites"". The crystal structure of hematite is trigonal-hexagonal. It has the same composition as maghemite; to distinguish between them, their chemical formulae are generally given as γ for hematite and α for maghemite. The other important class of strongly magnetic minerals is the iron sulfides, particularly greigite and pyrrhotite. Extraterrestrial environments being low in oxygen, minerals tend to have very little . The primary magnetic phase on the Moon is ferrite, the body-centered cubic (bcc) phase"
"Kamacite Kamacite is an alloy of iron and nickel, which is found on Earth only in meteorites. The proportion iron:nickel is between 90:10 and 95:5; small quantities of other elements, such as cobalt or carbon may also be present. The mineral has a metallic luster, is gray and has no clear cleavage although its crystal structure is isometric-hexoctahedral. Its density is about 8 g/cm and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen. The name was coined in 1861 and is derived from the Greek root ""καμακ-"" ""kamak"" or ""κάμαξ"" ""kamaks"", meaning vine-pole. It"
"Taenite Taenite (Fe,Ni) is a mineral found naturally on Earth mostly in iron meteorites. It is an alloy of iron and nickel, with nickel proportions of 20% up to 65%. The name is derived from the Greek ταινία for ""band, ribbon"". Taenite is a major constituent of iron meteorites. In octahedrites it is found in bands interleaving with kamacite forming Widmanstätten patterns, whereas in ataxites it is the dominant constituent. In octahedrites a fine intermixture with kamacite can occur, which is called plessite. Taenite is one of four known Fe-Ni meteorite minerals: The others are kamacite, tetrataenite, and antitaenite. It"
"Hashemite (mineral) Hashemite is a very rare barium chromate mineral with the formula Ba(Cr,S)O4. It is a representative of natural chromates - a relatively small and rare group of minerals. Hashemite is the barium-analogue of tarapacáite. It is also the chromium-analogue of baryte, and belongs to the baryte group of minerals. Hashemite is stoichiometrically similar to crocoite and chromatite. Hashemite is orthorhombic, with space group ""Pnma"". I was found together with chromium-bearing ettringite and an apatite group mineral in the Hatrurim Formation, known for the occurrence of rocks formed due to natural pyrometamorphism. Hashemite is named after the Hashemite Kingdom"
"of Jordan. Hashemite (mineral) Hashemite is a very rare barium chromate mineral with the formula Ba(Cr,S)O4. It is a representative of natural chromates - a relatively small and rare group of minerals. Hashemite is the barium-analogue of tarapacáite. It is also the chromium-analogue of baryte, and belongs to the baryte group of minerals. Hashemite is stoichiometrically similar to crocoite and chromatite. Hashemite is orthorhombic, with space group ""Pnma"". I was found together with chromium-bearing ettringite and an apatite group mineral in the Hatrurim Formation, known for the occurrence of rocks formed due to natural pyrometamorphism. Hashemite is named after the"
"ilmenite, anatase, pyrite, marcasite, lepidocrocite and goethite. Maghemite was named in 1927 for an occurrence at the Iron Mountain mine, northwest of Redding, Shasta County, California. The name alludes to somewhat intermediate character between MAGnetite and HEMatite. It can appear blue with a grey shade, white, or brown. It has isometric crystals. Maghemite is formed by the topotactic oxidation of magnetite. There is experimental and theoretical evidence that Fe(III) cations and vacancies tend to be ordered in the octahedral sites, in a way that maximizes the homogeneity of the distribution and therefore minimizes the electrostatic energy of the crystal. Maghemite"
"Wolframite Wolframite, (Fe,Mn)WO, is an iron manganese tungstate mineral that is the intermediate between ferberite (Fe rich) and hübnerite (Mn rich). Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives. Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite. This mineral was historically found in Europe in Bohemia, Saxony, and Cornwall. China reportedly has the world's largest supply of tungsten ore with about 60%. Other producers are Canada, Portugal, Russia, Australia, Thailand, South Korea, Rwanda, Bolivia, the United States, and the"
"minerals pyrrhotite and magnetite. Coyoteite Coyoteite is a hydrated sodium iron sulfide mineral. The mineral was named coyoteite after Coyote Peak near Orick, California where it was discovered (along with another rare mineral, orickite). This mineral is unstable under normal atmospheric conditions, making it rare at the surface. The mineral was first described in a petrographic study of a sample of a mafic diatreme at Coyote Peak. The largest piece of coyoteite found on that specimen has the dimensions of 0.2 × 0.4 mm. The chemical formula of the mineral is NaFeS·2HO. It was obtained by the analysis of five"
"It is named after Bruce Hapke, who predicted the presence and importance of vapor-deposited coatings on lunar soil grains (space weathering). Beside hapkeite, other natural iron silicide minerals include gupeiite, naqite, linzhiite, luobusaite, suessite, xifengite, and zangboite. Hapkeite Hapkeite is a mineral discovered in the Dhofar 280 meteorite found in 2000 in Oman on the Arabian peninsula. The meteorite is believed to originate from the Moon; specifically, it appears to be a fragment of lunar highland breccia. Hapkeite's composition is of silicon and iron, and it is similar to other silicon-iron minerals found on Earth. An impact on the Moon"
"transition. Hematite is part of a complex solid solution oxyhydroxide system having various contents of water, hydroxyl groups and vacancy substitutions that affect the mineral's magnetic and crystal chemical properties. Two other end-members are referred to as protohematite and hydrohematite. Enhanced magnetic coercivities for hematite have been achieved by dry-heating a 2-line ferrihydrite precursor prepared from solution. Hematite exhibited temperature-dependent magnetic coercivity values ranging from 289 to 5,027Oe. The origin of these high coercivity values has been interpreted as a consequence of the subparticle structure induced by the different particle and crystallite size growth rates at increasing annealing temperature. These"
"in Rainbow Lattice to be magnetite. A paper with these results will be published soon by authors from the Gemmological Institute, China University of Geosciences (Wuhan) and it will be published in The Journal of Gemmology by Gem-A. Hematite (Fe2O3) which are small mainly yellow to deep orange platelets which can be hexagonal shape and are generally in one plane within the feldspar. This effect is called aventurescence or ""sunstone effect"" which gives some of the gems an orange glow. Magnetite (FeO) iron oxide which creates the lattice effect. This forms as a very thin blades that occur in one"
"laboratory experiments originally intended to synthesize magnesium calcite, they had added cultures of ""Microcoleus chtonoplastes"" (cyanobacteria) to sea water brine. After 10 months of continuously shaking the samples they found huntite, magnesite, and aragonite. In 2012, Hopkinson et al. synthesized the mineral at 52 °C by reacting magnesium calcite with nesquehonite (MgCO·3HO). Huntite, dolomite and magnesite appear to be so very closely related, that a genetic relationship seems to be implied. In a number of instances all three carbonates are found in close association; for example Faust (1953) described huntite occurring together with dolomite and magnesite (amongst other minerals); Carpenter"
"as 0.1M HI or 2M NHCl and at 0.207 MPa at 416-800 °C, magnetite grew as crystals whose shapes were a combination of rhombic-dodechahedra forms. The crystals were more rounded than usual. The appearance of higher forms was considered as a result from a decrease in the surface energies caused by the lower surface to volume ratio in the rounded crystals. Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite, and the mineral pair forms a buffer that can control oxygen fugacity. Commonly, igneous rocks contain solid solutions of both"
"them in 1848. Concentrations of trace elements (germanium, gallium and iridium) are used to separate the iron meteorites into chemical classes, which correspond to separate asteroid parent bodies. Chemical classes that include hexahedrites are: Hexahedrite Hexahedrites are a structural class of iron meteorite. They are composed almost exclusively of the nickel-iron alloy kamacite and are lower in nickel content than the octahedrites. The nickel concentration in hexahedrites is always below 5.8% and only rarely below 5.3%. The name comes from the cubic (i.e. ""hexahedron"") structure of the kamacite crystal. After etching, hexahedrites do not display a Widmanstätten pattern, but they"
"Hexahedrite Hexahedrites are a structural class of iron meteorite. They are composed almost exclusively of the nickel-iron alloy kamacite and are lower in nickel content than the octahedrites. The nickel concentration in hexahedrites is always below 5.8% and only rarely below 5.3%. The name comes from the cubic (i.e. ""hexahedron"") structure of the kamacite crystal. After etching, hexahedrites do not display a Widmanstätten pattern, but they often do show Neumann lines: parallel lines that cross each other at various angles, and are indicative of impact shock on the parent body. These lines are named after Johann G. Neumann, who discovered"
"Aenigmatite Aenigmatite, also known as ""Cossyrite"" after Cossyra, the ancient name of Pantelleria, is a sodium, iron, titanium inosilicate mineral. The chemical formula is NaFeTiSiO and its structure consists of single tetrahedral chains with a repeat unit of four and complex side branches. It forms brown to black triclinic lamellar crystals. It has Mohs hardness of 5.5 to 6 and specific gravity of 3.74 to 3.85. Aenigmatite forms a solid-solution series with wilkinsonite, NaFeFeSiO. Aenigmatite is primarily found in peralkaline volcanic rocks, pegmatites, and granites as well as silica-poor intrusive rocks. It was first described by August Breithaupt in 1865"
"Ankerite Ankerite is a calcium, iron, magnesium, manganese carbonate mineral of the group of rhombohedral carbonates with formula: Ca(Fe,Mg,Mn)(CO). In composition it is closely related to dolomite, but differs from this in having magnesium replaced by varying amounts of iron(II) and manganese. It forms a series with dolomite and kutnohorite. The crystallographic and physical characters resemble those of dolomite and siderite. The angle between the perfect rhombohedral cleavages is 73° 48', the hardness is 3.5 to 4, and the specific gravity is 2.9 to 3.1. The color is white, grey or reddish to yellowish brown. Ankerite occurs with siderite in"
"Hapkeite Hapkeite is a mineral discovered in the Dhofar 280 meteorite found in 2000 in Oman on the Arabian peninsula. The meteorite is believed to originate from the Moon; specifically, it appears to be a fragment of lunar highland breccia. Hapkeite's composition is of silicon and iron, and it is similar to other silicon-iron minerals found on Earth. An impact on the Moon is thought to have launched the partially molten or vaporized material into orbit. Due to its 1:2 composition of silicon-iron, hapkeite was given the chemical formula FeSi. It occurs as opaque, yellowish to silvery microscopic isometric crystals."
"hysteresis. These parameters are then used to estimate mineral size and composition. The main contributors to the magnetic properties of rocks are the iron oxides, including magnetite, maghemite, hematite; and iron sulfides (particularly greigite and pyrrhotite). These minerals are strongly magnetic because, at room temperature, they are magnetically ordered (magnetite, maghemite and greigite are ferrimagnets while hematite is a canted antiferromagnet). To relate magnetic measurements to the environment, environmental magnetists have identified a variety of processes that give rise to each magnetic mineral. These include erosion, transport, fossil fuel combustion, and bacterial formation. The latter includes extracellular precipitation and formation"
"Zaratite Zaratite is a bright emerald green nickel carbonate mineral with formula NiCO(OH)·4HO. Zaratite crystallizes in the isometric crystal system as massive to mammillary encrustations and vein fillings. It has a specific gravity of 2.6 and a Mohs hardness of 3 to 3.5. It has no cleavage and is brittle to conchoidal fracture. The luster is vitreous to greasy. It is a rare secondary mineral formed by hydration or alteration of the primary nickel and iron bearing minerals, chromite, pentlandite, pyrrhotite, and millerite, during the serpentinization of ultramafic rocks. Hellyerite, NiCO·6HO, is a related mineral. It was found originally in"
"limestone and dolomite or in geodes. It is also found in nickel-iron meteorites, such as CK carbonaceous chondrites. Millerite was discovered by Wilhelm Haidinger in 1845 in the coal mines of Wales. It was named for British mineralogist William Hallowes Miller. The mineral is quite rare in specimen form, and the most common source of the mineral is in the Halls Gap area of Lincoln County, Kentucky in the United States. Millerite Millerite is a nickel sulfide mineral, NiS. It is brassy in colour and has an acicular habit, often forming radiating masses and furry aggregates. It can be distinguished"
"Willemite Willemite is a zinc silicate mineral (ZnSiO) and a minor ore of zinc. It is highly fluorescent (green) under shortwave ultraviolet light. It occurs in all different colors in daylight, in fibrous masses, solid brown masses (""troostite""), and apple green gemmy masses. It was discovered in 1830 and named after William I of the Netherlands. Willemite is usually formed as an alteration of previously existing sphalerite ore bodies, and is usually associated with limestone. It is also found in marble and may be the result of a metamorphism of earlier hemimorphite or smithsonite. It occurs in many places, but"
"Thaumasite Thaumasite is a silicate mineral with chemical formula CaSi(OH)(CO)(SO)·12HO. It occurs as colorless to white prismatic hexagonal crystals, typically as acicular radiating groups. It also occurs as fibrous masses. Its Mohs hardness is 3.5 and it has a specific gravity of 1.88 to 1.90. Optically it is uniaxial negative with indices of refraction of nω = 1.507 and nε = 1.468. It occurs as a hydrothermal alteration mineral in sulfide ore deposits and geothermal alteration of basalt and tuff. It occurs with zeolites, apophyllite, analcime, calcite, gypsum and pyrite. Thaumasite can also be formed along with other calcium silicate"
"source of the metal chromium. Chromitite Chromitite is an igneous cumulate rock composed mostly of the mineral chromite. It is found in layered intrusions such as the Bushveld Igneous Complex in South Africa, the Stillwater igneous complex in Montana and the Ring of Fire discovery in Ontario. Chromitite typically forms as orthocumulate layered lenses in peridotite rocks, at times intergrown with other oxides such as magnetite and ilmenite, and silicates such as olivine, pyroxene, plagioclase feldspar (mainly anorthite), and garnet crystals. The chromium rich garnet uvarovite forms in interbeded layers with chromitite. Chromitite is the main economic source for the"
"Khomyakovite Khomyakovite is an exceedingly rare mineral of the eudialyte group, with formula NaSrCaFeZrWSi(SiO)(SiO)O(O,OH,HO)(OH,Cl). The original formula was extended to show the presence of both the cyclic silicate groups and M4-site silicon, according to the nomenclature of the eudialyte group. Some niobium substitutes for tungsten in khomyakovite. Khomyakovite is an iron-analogue of manganokhomyakovite, the second mineral being a bit more common. The two minerals are the only group representatives, beside taseqite, with species-defining strontium, although many other members display strontium diadochy. Khomyakovite is the third eudialyte-group mineral with essential tungsten (after johnsenite-(Ce) and manganokhomyakovite). Khomyakovite, manganokhomyakovite, johnsenite-(Ce) and oneillite are"
"Chromitite Chromitite is an igneous cumulate rock composed mostly of the mineral chromite. It is found in layered intrusions such as the Bushveld Igneous Complex in South Africa, the Stillwater igneous complex in Montana and the Ring of Fire discovery in Ontario. Chromitite typically forms as orthocumulate layered lenses in peridotite rocks, at times intergrown with other oxides such as magnetite and ilmenite, and silicates such as olivine, pyroxene, plagioclase feldspar (mainly anorthite), and garnet crystals. The chromium rich garnet uvarovite forms in interbeded layers with chromitite. Chromitite is the main economic source for the mining of chromite and subsequent"
"Oldhamite Oldhamite is a calcium magnesium sulfide mineral with formula (Ca, Mg)S. Ferrous iron may also be present in the mineral resulting in the formula: (Ca,Mg,Fe)S. It is a pale to dark brown accessory mineral in meteorites. It crystallizes in the cubic crystal system, but typically occurs as anhedral grains between other minerals. It was first described in 1862 for an occurrence in the Bustee meteorite, Gorakhpur, Uttar Pradesh, India. It was named for Irish geologist Thomas Oldham (1816–1878), the Director of the Indian Geological Survey. It occurs as an interstitial mineral phase between silicate minerals in enstatite chondrite and"
"Huntite Huntite is a carbonate mineral with the chemical formula MgCa(CO). Huntite crystallizes in the trigonal system and typically occurs as platy crystals and powdery masses. The most common industrial use of huntite is as a natural mixture with hydromagnesite as a flame retardant or fire retardant additive for polymers. In 1953 a paper by George Faust announced the discovery of a new carbonate mineral found in Currant Creek, Nevada (US). Faust acknowledged that the mineral probably had been discovered previously, but it had been misidentified as impure magnesite by W. E. Ford in 1917. Faust named the new mineral"